The existence of pharmaceutical products capable of reducing the fever is known. Said pharmaceutical products are also known under the name of antipyretics. Typical antipyretic drugs are paracetamol, acetylsalicylic acid, niflumic acid, nimesulide, ketoprofen, flurbiprofen and some derivatives thereof.
The existence of substances able to change colour at a predetermined temperature is also known. Said substances are referred to as being “thermochromic”. Generally, said substances form part of the category of liquid crystals.
During the last few decades numerous inks based on thermochromic substances have been investigated. These inks are called “thermochromic inks” and are used for silk-screen printing, flexographic printing, wet offset printing, lithographic printing and the like.
Some of these inks are coloured and change colour at a predetermined temperature. Other thermochromic inks are colourless and become coloured at a predetermined temperature. There are also other inks which are coloured and become colourless at a predetermined temperature.
US 2006/0241355 discloses a healthcare base including an area to receive a bottle that carries a health-related substance for the user to take. The bottle can be provided with a thermometer obtained with a thermochromic paint. The temperature sensor includes a series of dots arranged in an array with two axes. One axis is in one degree interval, and the other is in 0.2 degree interval. To use the thermometer, the user can hold the bottle against his/her forehead for a duration of time. Then, the user pulls the bottle away from the forehead to read the temperature.